Introduction
LCM Calc ("we", "us", "our", "the Service") is committed to protecting your privacy. This Privacy Policy explains how we handle information when you visit and use our website and Least Common Multiple calculator.
We've written this policy in plain English wherever possible. If anything is unclear, please contact us — we're happy to explain.
Our Privacy-First Design
Most websites collect data because they run on servers. LCM Calc doesn't work that way — the entire calculator runs entirely inside your web browser. There is no backend calculating your answers, and no server storing your inputs.
No Backend Server
All math runs locally in JavaScript. Your numbers are never transmitted to us.
No Analytics Scripts
No Google Analytics, no Facebook Pixel, no advertising trackers of any kind.
No Accounts
No sign-up, no login, no email required. Use it anonymously every time.
No Third-Party Sharing
Because we don't collect data, we have nothing to sell, trade, or share.
This is privacy by architecture, not just by policy. Even if we wanted to collect your calculations (we don't), the way LCM Calc is built makes it technically impossible.
Information We Collect
We want to be completely transparent. Here's exactly what happens when you use LCM Calc:
Information we DO NOT collect:
- Your calculation inputs, results, or history
- Your name, email address, or phone number
- Your IP address, location, or device fingerprint
- Your browsing behavior across sites
- Any financial, health, or biometric information
Information we DO collect (limited):
- Contact form data — if you voluntarily submit a message via our Contact page, we receive your name, email address, category, subject, and message. This is used solely to reply to you.
- Basic server logs — our hosting provider may automatically log standard access data (IP address, timestamp, user agent) for security and abuse prevention. These logs are typically retained for 30 days and never analyzed for marketing.
- Local browser storage — the calculator stores your calculation history and theme preference locally in your browser's
localStorage. This never leaves your device.
| Type of Data | Collected? | Where Stored | Purpose |
|---|---|---|---|
| Calculation inputs | Never | Never sent anywhere | Not applicable |
| Calculation results | Never | Never sent anywhere | Not applicable |
| Calculation history | Local only | Your browser's localStorage |
Restore recent calculations |
| Theme preference | Local only | Your browser's localStorage |
Remember your dark/light choice |
| Contact form data | On submit | Email inbox only | Reply to your message |
| Server access logs | Automatic | Hosting provider (30 days) | Security & abuse prevention |
| Analytics / tracking | Never | Not applicable | Not applicable |
How We Use Information
Because we collect so little information, the ways we can use it are extremely limited. Here's the complete list:
Replying to Messages
If you submit the contact form, we use your email to respond to your question.
Security & Abuse
Server logs help us detect and prevent attacks, spam, and abuse.
Improving the Service
Feedback you send helps us decide what to build or fix next.
We never use your information for advertising, profiling, AI training, resale, or any purpose other than the three listed above.
Cookies & Tracking Technologies
LCM Calc does not use:
- Advertising cookies — no ad networks, no retargeting.
- Analytics cookies — no Google Analytics, no Mixpanel, no Hotjar.
- Social media pixels — no Facebook Pixel, no TikTok Pixel.
- Fingerprinting scripts — no canvas, audio, or WebGL fingerprinting.
- Cross-site tracking — we don't track you across other websites.
We may use:
- LocalStorage (not cookies) — to save your theme preference and optional calculation history. This is browser-only, device-specific, and never transmitted.
- Session cookies (only if technically required) — for essential security functions such as CSRF protection. These are not used for tracking.
Local Storage (Browser Data)
LCM Calc uses your browser's localStorage API to remember a few things between visits. This data is stored only on your device and is never sent to us.
| Key | What It Stores | Purpose | How to Clear |
|---|---|---|---|
lcm-pro-history-v2 |
Up to 50 recent calculations | Restore recent inputs | Click "Clear" in History panel |
lcm-pro-theme |
"dark" or "light" | Remember theme choice | Toggle theme or clear site data |
lcm-pro-lang |
Language code (e.g. "en", "hi") | Remember language choice | Change language or clear site data |
lcm-pro-view |
Last active tab | Restore your last view | Switch tabs or clear site data |
None of this data is accessible to us or any third party. It lives exclusively in your browser's sandboxed storage, on your device.
Third-Party Services
We keep third-party involvement to an absolute minimum. Here are the only external services that may be involved when you use LCM Calc:
- Web hosting provider — the website is served by a hosting provider, which may log standard access data (IP address, timestamp, user agent) for security. This data is not used for marketing or profiling.
- Browser APIs — the Web Speech API (for voice input) and localStorage are native browser features, not third-party services. No data is sent to Google, Apple, or Microsoft unless you explicitly use voice input, in which case your browser's own speech engine handles it locally or per your browser's own privacy terms.
We do not use Google Fonts, Google Analytics, Cloudflare Insights, or any other third-party script that would introduce tracking. All fonts, icons, and assets are either system-native or embedded in the page.
Data Retention
Because we collect so little, retention is simple:
| Data Type | Retention Period |
|---|---|
| Calculation history | On your device until you clear it (never expires automatically) |
| Theme preference | On your device until you clear it |
| Language preference | On your device until you clear it |
| Contact form messages | In our email inbox for up to 12 months, then archived or deleted |
| Server access logs | Typically 30 days (hosting provider policy) |
Data Security
Even though we collect very little, we still take security seriously. Here's what we do:
- HTTPS everywhere — all traffic to and from the site is encrypted with TLS.
- Content Security Policy — our pages define strict CSP headers to prevent injection attacks.
- No third-party scripts — fewer dependencies means fewer attack vectors.
- Regular updates — we keep our hosting environment patched and monitored.
- Local-first architecture — the best way to secure data is to never collect it in the first place.
Your Privacy Rights
Depending on where you live, you may have specific legal rights over your personal data. Because LCM Calc collects almost no personal data, most of these rights are trivially satisfied — but we want you to know them anyway.
Right to Access
You can request a copy of any personal data we hold about you.
Right to Deletion
You can request that we delete any personal data we hold about you.
Right to Correct
You can request correction of any inaccurate data we hold.
Right to Object
You can object to any processing of your personal data.
Right to Portability
You can request your data in a portable, machine-readable format.
Right to Withdraw
You can withdraw consent at any time where consent was the basis.
To exercise any of these rights, please email privacy@lcmcalc.com. We'll respond within 30 days as required by GDPR, or 45 days as required by CCPA.
Children's Privacy
LCM Calc is a general-audience educational tool and is designed to be safe for learners of all ages. We comply with the Children's Online Privacy Protection Act (COPPA) and similar regulations worldwide.
Because we do not collect personal information from anyone — regardless of age — we do not knowingly collect personal information from children under 13. If you are a parent or guardian and believe we have inadvertently collected information about your child, please contact us immediately at privacy@lcmcalc.com and we will delete it.
Teachers and parents: LCM Calc is safe to share with students. The calculator collects no user data, displays no ads, and links to no external content that would be inappropriate for children.
International Users
LCM Calc is available worldwide and translated into 19 languages. Because we don't operate a data-collecting backend, the concept of "international data transfers" barely applies to us:
- Your calculations never cross any border — they stay on your device.
- If you contact us via the Contact form, your message may be stored on email servers located in the country where our email provider operates.
For users in the European Economic Area (EEA), UK, or Switzerland: our approach is compliant with GDPR by design, since we do not engage in large-scale personal data processing. For users in Brazil: we respect your rights under the LGPD. For users in California: we respect your rights under the CCPA and CPRA.
Do Not Track (DNT)
Some browsers offer a "Do Not Track" (DNT) feature that sends a signal to websites requesting that they not track you. Because LCM Calc does not track you in the first place, DNT settings have no practical effect on our site — but we fully respect them.
Regardless of whether you have DNT enabled, we will never track you, profile you, or serve you targeted advertising.
Changes to This Policy
We may update this Privacy Policy from time to time to reflect changes in our practices, technology, or legal requirements. When we do:
- We will update the "Last updated" date at the top of this page.
- For material changes, we will add a visible notice on the Website for a reasonable period.
- If the change significantly affects how we handle your data, we will do our best to notify you directly (for example, via a banner on the calculator).
Your continued use of LCM Calc after any changes to this Privacy Policy constitutes your acceptance of those changes. We encourage you to review this page periodically to stay informed.
Contact Us
If you have any questions, concerns, or requests relating to this Privacy Policy or our handling of your personal data, please contact us. We aim to respond to all privacy-related inquiries within 2–3 business days.
Privacy team
For privacy questions, data requests, or to report a concern.
Frequently Asked Questions
Do you really not collect my calculations?
Correct. Every calculation runs entirely in your browser using JavaScript. There is no backend server that receives your inputs. Even if you open your browser's developer tools and watch the network tab, you'll see no requests being sent when you calculate — because there aren't any.
Can you see my calculation history?
No. Your calculation history is stored only in your browser's localStorage, which is sandboxed by the browser and inaccessible to us. You can clear it any time with the "Clear" button in the History panel.
Do you use cookies?
We don't use tracking cookies. We may use minimal session cookies strictly for security (such as CSRF protection), but no analytics, advertising, or profiling cookies. Everything else is stored via localStorage, not cookies.
What happens when I submit the contact form?
Your name, email, category, subject, and message are sent to us so we can reply. That's it. We don't add you to a mailing list, we don't sell your email to anyone, and we don't use it for marketing. We keep messages for up to 12 months and then delete or archive them.
Will you ever add analytics or ads in the future?
No. LCM Calc is committed to remaining free, ad-free, and tracker-free forever. If we ever needed to introduce a change (which we don't plan to), we would notify users prominently and update this policy first.
Is it safe to use LCM Calc in a school or classroom?
Yes. LCM Calc is COPPA-compliant and collects no personal information from anyone, regardless of age. It shows no ads, has no social features, and links to no external content that could be inappropriate for students. Teachers and parents can share it freely.
How do I exercise my GDPR or CCPA rights?
Email privacy@lcmcalc.com with the specific right you'd like to exercise (access, deletion, correction, portability, etc.). Because we hold almost no data about you, most requests will be resolved immediately — often confirming that we hold nothing.
Does voice input send audio to a server?
Voice input uses your browser's native Web Speech API. Depending on your browser (Chrome, Edge, Safari), audio may be processed by the browser vendor's own speech recognition service — this is controlled by your browser and its privacy settings, not by us. LCM Calc never receives or stores any audio.
Can I use LCM Calc offline?
Yes. LCM Calc is a Progressive Web App (PWA). Once loaded, all calculations work without an internet connection. When offline, absolutely nothing about your usage is transmitted — for the simple reason that nothing ever is.
I still have questions about privacy. What should I do?
Please email privacy@lcmcalc.com. We take every privacy question seriously and will respond within 2–3 business days with a clear, honest answer.